The biosynthetic gene cluster of pantocin A provides insights into biosynthesis and a tool for screening

Peptide origins: Feeding experiments carried out with 14C-labeled amino acids have demonstrated that the bicyclic core of pantocin A is derived from glutamate or glutamine residues. Sequencing and transposon mutagenesis of the 3.5 kb stretch of DNA that enables an Escherichia coli strain to produce pantocin A has identified three major open-reaing frames (paaA, paaB, and paaC) responsible for its construction, and the resistance mechanism (see picture red: inactive, green: active, yellow: reduced activity positions).